TARN, a department of France, formed in 1790 of the three dioceses of Albi, Castres and Lavaur, belonging to the province of Languedoc. Pop. (1931) 302,994. Area, 2,231 sq. miles. Tarn is bounded north and east by Aveyron, south-east by Herault, south by Aude, south-west and west by Haute-Garonne, north west by Tarn-et-Garonne. The department forms the southern buttress of the Plateau Central, with the Montagne Noire (3,97o ft.) near its southern border. The general slope is from east to west, and in the east the Monts de Lacaune reach 4,154 ft. at the Pic de Montalet. The greater part of the department is floored by ancient rocks with some granite, especially in the north, and the general level is from 1,500 to 2,000 feet. The Aveyron runs along the northern boundary, the Tarn across the middle of the department, and the Agout across the south, and they join one another west of the boundary on their way to Garonne. The Aude receives the streams from a part of the Montagne Noire. The limestone and sandstone foot-hills are clothed with vines and fruit trees, and are broken by deep alluvial valleys of extraor dinary fertility. The eastern portion of the department has the climate of Auvergne, the severest in France, but that of the plain is Girondin. The winter average temperature reduced to sea level is 41° and the summer average temperature is 7o°, but the great elevation often reduces these figures by 15° to 20°. The
rainfall, 29 or 3o in. at that place, exceeds 4o in. on the Lacaune and Montagne Noire.
The west and centre produces cereals, wheat, oats, maize, and vines; the valleys around Castres provide natural pasture for cattle; market-gardening is carried on in the west. There are mines of coal and iron, and quarries of lime. The industries include the manufacture of textiles, hosiery, brushes, morocco leather, hats, metal foundries, dye-works and glass-works. The department is famous for its sparkling wines. The department is divided into two arrondissements (Albi and Castres) and there are 36 cantons and 323 communes. The department is in the 16th military region, and the academie (educational division) of Tou louse, where is its court of appeal.
The chief towns are Albi, the capital and seat of an archbishop, with suffragan bishops at Rodez, Cahors, Mende and Perpignan, Castres, Gaillac, Lavaur, Mazamet and Cordes (qq.v.). Burlats has ruins of an old church and chateau ; Lisle d'Albi, a bastide with a 14th century church, and Penne has ruins of a mediaeval château.